JPH07261629A - Image forming device - Google Patents

Abstract

PURPOSE:To provide an image forming device capable of preventing the oblique advancing of a recording medium and the occurrence of jamming by surely positioning and fixing a door to a device main body. CONSTITUTION:The image forming device which is provided with a paper ejecting door 10 for ejecting the recording medium on which a visible image is fixed to the outside of the device main body 100 and capable of being opened/ closed, and where the door 10 is positioned and fixed to the device main body 100 by engaging a pair of hooks 15F and 15R arranged before and behind the door 10 with a pin(part to be hooked) 17 on the device main body 100 side is provided with an elastic member 25 generating reaction force F corresponding to external force FS and FB acting on the door 10. Thus, the reaction force F corresponding to the external force FS and FB acting on the door 10 in a state where the door 10 is closed acts on the door 10 from the member 25, so that the torsional deformation of the door 10 is prevented and the door 10 is surely positioned and fixed to the device main body 100, then the oblique advancing of the recording medium and the occurrence of jamming are prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine or a printer which employs an electrophotographic system or an electrostatic recording system.

[0002]

2. Description of the Related Art FIG. 4 shows a color electrophotographic copying machine as a typical example of such an image forming apparatus.

That is, FIG. 4 is a vertical cross-sectional view showing the basic structure of a color electrophotographic copying machine.
A photosensitive drum 1, which is an image bearing member, is rotatably supported in the direction of the arrow in the drawing, and around the photosensitive drum 1, a corona charger 2, an optical system 3, a developing device 4, a transfer device 5 and A cleaning device 6 is provided.

The optical system 3 is a laser beam exposure apparatus which is composed of a document scanning section and a color separation filter, and is a color beam separated light image or a light image E corresponding thereto on the photosensitive drum 1. To irradiate.

On the other hand, the surface of the photosensitive drum 1 is uniformly charged by the charger 2, and as described above, the latent image is formed on the surface of the photosensitive drum 1 upon receiving the light image E for each separated color. The latent image is developed as a toner image by the developing device 4.

The developing device 4 is constructed as a rotary developing device, which comprises four developing devices around the central axis 4b, namely:
It has a black developing device 4BK, a cyan developing device 4C, a magenta developing device 4M and a yellow developing device 4Y, and rotates a predetermined developing device (4BK, 4C, 4M, 4Y) to a developing position facing the photosensitive drum 1. Let the developing device (4BK, 4
C, 4M, 4Y) develops the latent image formed on the photosensitive drum 1 to form a resin-based toner image on the photosensitive drum 1 as described above.

On the other hand, the recording material P stored in the recording material cassette 7 is passed one by one through a conveying system (according to a paper path indicated by a broken line in FIG. 4) at a position where the transfer device 5 and the photosensitive drum 1 face each other ( The toner image formed on the photosensitive drum 1 is transferred onto the recording material P supplied to the transfer nip portion). The transfer device 5 includes a transfer drum 5a that is rotatably supported, a transfer corona charger 5b, a suction corona charger 5c for electrostatically sucking the recording material P, and a suction facing the suction corona charger 5c. Roller 5g, inner corona charger 5
d and the outer corona charger 5e, and a recording material carrying sheet 5f made of a dielectric sheet such as a polycarbonate film is integrally stretched in a cylindrical shape in the opening area of the peripheral surface of the transfer drum 5a.

When the drum-shaped transfer drum 5a is rotated in the direction of the arrow shown in the figure, the recording material P is carried on the recording material carrying sheet 5f and rotated together with the transfer drum 5a, and the recording material P is transferred onto the photosensitive drum 1. Toner image is transferred onto the recording material P by the transfer corona charger 5b.

As described above, a desired number of color images are transferred onto the recording material P which is attracted to and conveyed by the recording material carrying sheet 5f, and as a result, a full-color unfixed toner image is formed on the recording material P. It is formed.

When a full-color image is formed, when the transfer of the four color (yellow, cyan, magenta, black) toner images to the recording material P is completed as described above, the recording material P is transferred to the transfer drum by the separating means 8. The recording material P separated from 5a is conveyed to the heat roller fixing device 9 to be fixed with the toner image, and then discharged to the outside of the apparatus main body 100 by the discharge roller pair 11 provided in the discharge door 10. Then, they are stacked on the tray 12.

After the transfer, the photosensitive drum 1 is cleaned of residual toner on its surface by the cleaning device 6, and
It is subjected to the image forming process again.

By the way, the paper discharge door 10 is constructed so as to be openable and closable for the purpose of jam handling and maintenance improvement on the downstream side of the heat roller fixing device 9. That is, the lower end of the paper discharge door 10 is rotatably pivoted by the support shaft 13, and is opened and closed by rotating about the support shaft 13 in the directions of arrows A and B in the drawing.

Thus, the apparatus main body 100 of the paper discharge door 10 described above.
Conventionally, there are various types of means for positioning and fixing to the side, such as one that uses the attractive force of a magnet, one that uses a snap fit, and one that uses a hook, but a relatively strong holding force is secured. Those that use hooks that do not require adjustment sets are generally widely used. An example thereof is shown in FIG.

That is, FIG. 5 is a perspective view of the electrophotographic copying machine showing the positioning and fixing structure of the paper discharge door 10. At the upper part of the paper discharge door 10, a stay 14 which is long in the width direction is horizontally provided. The stay 15 is rotatably supported in the directions of arrows a and b, and hooks 15 are integrally formed at both ends of the stay 14.
A grip 16 to be gripped by the user at the time of opening / closing the discharge door 10 is attached to the center of the stay 15 in the width direction. The stay 14 and the hook 15 are urged in the arrow a direction (engagement direction) by urging means (not shown).

Then, as shown in FIG. 5, when the paper discharge door 10 is opened, the paper discharge door 10 is rotated about the shaft 13 in the direction of arrow B to be closed, and the hook 15 is closed. 1
The pair of pins 17 projectingly face each other on the 00 side are engaged with each other, whereby the paper discharge door 10 is positioned and fixed on the apparatus main body 100 side and the closed state thereof is maintained.

In order to open the discharge door 10 in the closed state by the user for jam clearance, maintenance, etc., the user holds the handle 16 and moves it toward the front side (arrow A in FIG. 5).
Direction). Then, the stay 14 and the hook 15 integrally rotate in the direction of arrow b in FIG. 5 in conjunction with the operation of pulling the handle 16 by the user, and the engagement with the pin 17 of the hook 15 is released. 10 is opened by rotating in the direction of arrow A about the support shaft 13.

[0017]

However, according to the conventional positioning and fixing structure of the paper discharge door 10, as shown in FIG. 6, the size of the groove 15a of the hook 15 is larger than that of the pin 17. It is set to be slightly larger, and the ejection door 10 is positioned by abutting the abutting surface 15b of the hook 15 against the pin 17 by the urging force in the direction of the arrow a in the figure, so that the hook 15 accurately abuts on the pin 17. If it does not hit, the position of the discharge roller pair 11 moves back and forth with respect to the conveying direction of the recording material P, or tilts, and due to these, skew or jam of the recording material P conveyed from the heat roller fixing device 9 may occur. Occur.

Therefore, an object of the present invention is to provide an image forming apparatus capable of reliably positioning and fixing the door with respect to the apparatus main body to prevent the skew or jam of the recording medium. is there.

Further, as a method of abutting the hook 15 on the pin 17, an elastic member (not shown) is used to open an arbitrary position of the paper ejection door 10 in a direction in which the paper ejection door 10 is opened (the hook 15 abuts on the pin 17). Direction) there is a method of urging with an arbitrary force.

However, the frame of the actual delivery door 10 is formed by a molding method or the like, and this is not a completely rigid body, and particularly in the case of the delivery door 10 having low rigidity, the magnitude and action of the urging force. The frame is twisted and deformed depending on the point, and 2
One of the two hooks 15 is butted against the pin 17,
A situation may occur in which the other hook 15 does not hit. Furthermore, in an extreme case, only one hook 15 engages with the pin 17 and the other hook 15 does not engage with the pin 17, a so-called one-side closed state occurs, which the user does not notice in that state. A situation may occur in which the image forming operation is started.

By the way, since the power is normally turned off / on in synchronization with the opening / closing of the paper discharge door 10, when the paper discharge door 10 is closed, the frame of the paper discharge door 10 or the like does not operate in conjunction with this operation. Output door 10 for pressing the illustrated micro switch
Is acted upon by a reaction force from a micro switch, and a driving roller such as a pair of discharging rollers 11 (see FIG. 4) is applied to the discharging door 10 by a load torque when the driving force is transmitted by a gear (not shown). The external force acts on the sheet discharge door 10 by these forces, and the sheet discharge door 10 is pressed in the opening direction (the direction in which the hook 15 contacts the pin 17).

Therefore, when the paper discharge door 10 is closed, various forces are actually applied to the paper discharge door 10. However, it is designed to apply these forces to the paper discharge door 10 in a well-balanced manner. Since it is difficult, the sheet discharge door 10 having low rigidity is twisted and deformed, which causes the same problem as described above.

Therefore, the object of the present invention is to confirm that the door is surely closed, and to make the image forming operation impossible in other states to improve the reliability. To provide a forming apparatus.

The above-mentioned problem is not limited to the paper discharge door, and similarly occurs in a door having a recording material conveyance path integrally.

[0025]

[Means for Solving the Problems] In order to achieve the above object,
According to a first aspect of the present invention, an image forming apparatus that transfers a visible image formed on an image bearing member to a recording medium according to image information and discharges the recording medium outside the apparatus main body is provided with a recording medium conveyance path. An openable and closable door, a pair of hooks provided on the left and right sides of the door, a hook receiving portion provided on the device body side, and an external force that acts on the door when the door is closed. And an elastic member that produces a reaction force commensurate with.

According to a second aspect of the present invention, in the above-mentioned first aspect of the invention, the door is opened or closed by maintaining the actuator against the elastic force of the door on either the left or right side of the door. Opening / closing detecting means for detecting is provided, and a handle to be gripped at the time of opening / closing operation of the door is provided closer to the side opposite to the side where the opening / closing detecting means is provided with respect to the door center line.

According to a third aspect of the present invention, in the first aspect of the present invention, the opening / closing detection means for detecting the opening / closing of the door is provided on either the left or right side of the door, and the opening / closing detection means is provided. The contact angle of the hook on the side opposite to the side provided with the hook receiving portion is set to be smaller than that of the other hook.

According to a fourth aspect of the present invention, in the second or third aspect of the invention, the door has at least a pair of paper discharge rollers, and the driving force transmitting means to the paper discharge rollers and the opening / closing detection. The means are provided on the same side with respect to the door center line.

The invention according to claim 5 is the same as claim 2 or 3
Alternatively, in the invention described in 4, the image forming operation is disabled when the open / close detection unit detects that the door is in the open state.

[0030]

According to the first aspect of the present invention, since the reaction force corresponding to the external force acting on the door when the door is closed acts on the door from the elastic member, twisting deformation of the door is prevented and the door is installed in the main body of the apparatus. It is possible to reliably position and fix the recording medium to prevent the recording medium from being skewed or jammed.

According to the invention described in claim 2, in the invention described in claim 1, since the handle is provided on the side opposite to the side where the opening / closing detection means is provided with respect to the center line of the door, when the door is closed. The side where the opening / closing detection means is provided is more likely to be twisted than the other side with the handle of the door as a boundary. Therefore, when the door is partially closed, the side with less twist is always closed, and the easily twisted side is opened. In such a case, the user can confirm that the door is completely closed by the detection of the opening / closing detection means installed on the side that is easily twisted.

According to the invention of claim 3, in the invention of claim 1, since the hook on the side opposite to the side on which the opening / closing detecting means is provided has a smaller contact angle with the hook receiving portion, It is easier for the hook to smoothly engage with the hook receiving portion, and when the door is closed, the side provided with the opening / closing detection means of the door must be opened, which is the same as the invention according to claim 2. The effect is obtained.

According to the invention described in claim 4, in the invention described in claim 2 or 3, the driving force transmitting means to the paper discharge roller and the opening / closing detecting means are provided on the same side with respect to the door center line. When it is confirmed by the opening / closing detection means that the door is completely closed, at the same time, a reliable mechanical operation of the driving force transmission means is ensured, and a stable operation of the paper discharge roller is ensured.

According to the invention of claim 5, claim 2
In the invention described in 3 or 4, when the opening / closing detection means detects that the door is at least partially closed, the image forming operation is disabled, and thus the door is fully closed. Therefore, the problem that the image forming operation is started without the user's knowledge is solved.

[0035]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

<First Embodiment> FIG. 1 is a perspective view of a paper discharge section of an image forming apparatus according to the first embodiment of the present invention. The other construction of the image forming apparatus is the same as that of the conventional one shown in FIG. Since it is similar to that of the image forming apparatus (color electrophotographic copying machine), description thereof will be omitted.

In FIG. 1, 101F and 101R are respectively a front side plate and a rear side plate of the main body 100 of the apparatus. The front side plate 101F and the rear side plate 101R have a paper discharge door 10 whose lower end is rotated by a spindle 13. It is movably supported. That is, the support plate 18 is provided in front of and behind the inside of the frame of the discharge door 10.
F and 18R are arranged in parallel with each other, and each support plate 18
As described above, the paper ejection door 10 is provided with the front side plate 1 by the support shafts 13 projecting outward from the lower ends of the F and 18R.
01F and the rear side plate 101R are rotatably supported.
The discharge door 10 is allowed to rotate by an angle of 90 ° in the directions of arrows A and B (opening / closing direction) around the support shaft 13 by a stopper member (not shown). Arrow A from the closed state shown as the center
It is rotated in the direction and opened.

A pressing portion 18F projecting inward of the apparatus main body 100 is provided at each upper end of the supporting plates 18F and 18R.
-1, 18R-1 are integrally formed, and both support plates 18
A stay 14 is rotatably pivoted by a shaft 19 and horizontally laid between the upper portions of F and 18R, and hooks 15F projecting inward of the apparatus main body 100 are provided at both ends of the stay 14. , 15R are integrally formed. A grip 16 is attached to the center of the stay 14 in the width direction (on the center line in the width direction of the discharge door 10 (hereinafter, abbreviated as the discharge door center line) M) so that the user can grip the grip 16. The stay 14 is in the direction of the arrow a shown by the urging means (not shown) (the direction in which the hooks 15F and 15R engage with the pin 17 described later).
Is urged by. In addition, each hook 15F, 15R is formed with a recessed groove 15a to be engaged with a pin 17 described later, and both hooks 15F, 15R are arranged in symmetrical positions with respect to the center line M of the discharge door. .

Further, below the stay 14, between the two supporting plates 18F and 18R, a rotary shaft 20 is provided with a bearing 21.
It is rotatably provided and horizontally laid parallel to the stay 14, and two drive rollers 11a are connected to the central portion between both bearings 21 of the rotary shaft 20. A driven roller 11b, which is paired with the drive roller 11a and has a small diameter, is pressed against each drive roller 11a, and the drive roller 11a and the driven roller 11b are paired with the paper discharge roller pair 11 (see FIG. 4).
See).

A gear G1 is connected to an end of the rear side support plate 18R of the rotary shaft 20 extending outward, and the gear G1 is rotationally driven by a motor (not shown). The gear G2 connected to the end of the drive shaft 22 is meshed.

On the other hand, the front side plate 101 of the apparatus main body 100
F and the rear side plate 101R are pins 17 which are hook receiving portions to be engaged with the respective concave grooves 15a of the hooks 15F and 15R.
Are projected to face each other. And the body rear side plate 10
In 1R, the apparatus main body 1 is interlocked with the opening / closing operation of the discharge door 10.
00 is provided with a micro switch 23 for turning on / off an AC power source (not shown). When the opening / closing door 10 is closed as shown in the drawing, the switch lever 24 provided on the main body rear side plate 101R causes the rear side support plate to move. 18R pressing part 18R-
When it is pressed by 1, the micro switch 23 is operated to turn on the AC power source, and the opening / closing door 10 pivots around the support shaft 13 in the direction of the arrow A in the drawing to open, the switch lever 24 separates from the micro switch 23. Then, the AC power source is turned off to deactivate the micro switch 23.

An elastic member 25 made of a thin plate spring is attached to a mounting base 26 by a screw 27 at a position symmetrical to the switch lever 24 with respect to the center line M of the discharge door of the front plate 101F of the main body. When the paper discharge door 10 is closed, the pressing portion 18F-1 provided at the upper end of the front support plate 18F presses the elastic member 25 with a predetermined force.

When the paper discharge door 10 is closed as shown in the drawing, the hooks 15F and 15R are engaged with the pins 17 to keep the paper discharge door 10 closed. The pressing portion 18R-1 of the rear side support plate 18R presses the switch lever 24 to push the micro switch 23 as described above.
Is operated to turn on the AC power source, and the pressing portion 18F-1 of the front support plate 18F presses the elastic member 25 with a predetermined force. For this reason, the paper discharge door 10 is attached to the rear support plate 18 as shown in the drawing.
The micro switch 23 (switch lever 24) at the contact point of the R pressing portion 18R-1 with the switch lever 24
From the outside (direction to open the discharge door 10 in the direction of arrow A) from the reaction force F _S, and presses the pressing portion 18 of the front support plate 18F.
At the contact point of F-1 with the elastic member 25, the elastic member 25
Receives an outward reaction force F (in the direction of the arrow in the figure).

When the image forming operation of the image forming apparatus is started and the drive shaft 22 is rotationally driven by a motor (not shown), the drive shaft 22 is rotated by the gears G2, G.
1 is transmitted to the rotary shaft 20, and the rotary shaft 20 and the drive roller 11a bound to the rotary shaft 20 are rotationally driven in the direction of the arrow in the figure, and the heat roller fixing device 9 (see FIG. Recording material P conveyed by
Is discharged to the outside of the machine by the pair of discharge rollers 11. At this time, the discharge door 10 applies a force F _{B in the} opening direction of the bearing 2 of the rear support plate 18R by the additional torque between the gears G1 and G2.
Receive at the mounting part of 1. Depending on the arrangement of the gears G1 and G2 and the center of rotation of the paper discharge door 10, the paper discharge door 10 has the force F _B.
Receives a force in the opposite direction.

Therefore, if the elastic member 25 is not provided, the discharge door 10 receives the reaction force F _S and the force F _B only on the one rear support plate 18R, so that the discharge door 10 with low rigidity is provided. The rear side is twisted and deformed toward the open side with respect to the front side.

However, in this embodiment, the reaction force F from the elastic member 25 acts on the front support plate 18F, so that the force F, the reaction force F _S, and the force F _B are balanced on the sheet discharge door 10. It works well, and as a result, twisting deformation of the paper discharge door 10 is prevented. In particular, in the present embodiment, the sum of the respective moments of the reaction force F _S and the force F _B acting on the rear support plate 18R around the discharge door center line M and the discharge door rotation center line N is applied to the front support plate 18F. The spring constant of the elastic member 25 is determined so as to be equal to the moments about the center lines M and N of the acting reaction force F.

That is, here, the horizontal components of the reaction force F _S , the force F _B, and the distance from the center line M of the reaction force F are L _SH , L _BH , and L _H , respectively, as shown in the figure, and the center line N Assuming that the vertical components of the distance are L _SV , L _BV , and L _V , respectively, the following equation of moment balance:

[0048]

[Equation 1] F · L _H = F _S · L _SH + F _B · L _BH (1) F · L _V = F _S · L _SV + F _B · L _BV (2) The reaction force F is satisfied. Thus, the spring constant of the elastic member 25 is determined.

Further, according to this embodiment, the reaction force F _S and the force F _{B are}
Since the reaction force F and the reaction force F both act in the direction of opening the paper discharge door 10, the hooks 15F and 15R are securely engaged with the pins 17, and therefore the paper discharge door 10 is accurately positioned and fixed to the apparatus main body 100. Further, since the recording material P is reliably discharged, the recording material P conveyed from the heat roller fixing device 9 does not move back and forth with respect to the conveying direction of the recording material P and is not inclined. No skew or jam will occur.

By the way, in order to open the discharge door 10 in the closed state for jam clearance or maintenance, the user holds the handle 16 and pulls it toward the front side (direction of arrow A in FIG. 1). good. Then, the stay 14 and the hooks 15F and 15R are interlocked with the operation of pulling the handle 16 by the user.
Rotate integrally in the direction of arrow b in FIG.
Since the engagement with the pin 17 of the 5R is released, the discharge door 10
Is opened by rotating in the direction of arrow A about the support shaft 13.

In order for the user to close the discharge door 10 opened as described above, the user should hold the handle 16 and push it toward the back side (direction of arrow B in FIG. 1). Then, the sheet discharge door 10 rotates in the direction of the arrow B in the drawing around the support shaft 13, the hooks 15F and 15R engage with the pins 17, the sheet discharge door 10 is positioned and fixed, and the closed state is maintained. It In this case, both support plate 18F of Haishitobira 10, 18R are substantially equal the reaction force F, since it is biased outward (direction Haishitobira 10 is opened) by the F _S, these supporting plate 18F ，
The hooks 15F and 15R supported by 18R securely engage with the pin 17 with substantially the same force. Therefore, the hook 15F,
The probability that a so-called one-sided state in which only one of 15R engages with the pin 17 and the other does not engage with the pin 17 is suppressed to a low level.

In this embodiment, the elastic member 25 is composed of a thin plate spring, but it may be composed of a coil spring or the like. <Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a perspective view of the paper discharge unit of the image forming apparatus according to the second embodiment of the present invention. In this figure, the same elements as those shown in FIG. A description thereof will be omitted.

In the present embodiment, the opening / closing (not shown) for detecting the opening / closing of the paper discharge door 10 by the operation of the switch lever 24 installed on the rear side of the paper discharge door 10 (that is, the opening / closing operation of the paper discharge door 10). A detection sensor is provided, and the handle 16 is attached to the front side of the discharge door center line M (on the side opposite to the side where the open / close detection sensor is provided), and other configurations are the same as those of the first embodiment. It is similar to that of.

Then, as described above, the handle 16 is moved to the center line M.
On the other hand, when it is attached to the front, the rear side is more likely to be twisted with the handle 16 of the discharge door 10 as a boundary when the discharge door 10 is closed than the front side.

Therefore, when the paper discharge door 10 is closed on one side, the front side, which is less twisted, is always closed, and the rear side, which is easily twisted, is opened. In such a case, the opening / closing detection sensor installed on the rear side is opened. The user can confirm that the discharge door 10 is completely closed by the detection of.

Further, since the open / close detection sensor and the gears G1 and G2 for transmitting the driving force are provided on the same side (rear side) with respect to the discharge door center line M, the open / close detection sensor detects the discharge door 10. When it is confirmed that the gears G1 and G2 are completely closed, it means that the gears G1 and G2 are also meshed with each other at the same time, and a reliable mechanical operation including the meshing of the gears G1 and G2 is ensured, which is not shown. Motors to gears G2, G1
The power is surely transmitted to the rotary shaft 20 through the above, and the stable operation of the paper discharge roller pair 11 (see FIG. 4) is ensured.

Further, the paper discharge door 10 is opened by the open / close detection sensor.
When it is detected that the paper is at least partially closed, the image forming operation can be disabled. With this configuration, it is possible for the user to know that the paper discharge door 10 is in the single closed state. The conventional problem that the image forming operation is started without noticing is solved.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIG. Incidentally, FIG. 3 is a side view of the paper discharge door showing the third embodiment of the present invention.

In this embodiment, similarly to the second embodiment, the discharge door is operated by the operation of the switch lever (not shown) installed on the rear side of the discharge door 10 (that is, the opening / closing operation of the discharge door 10). An open / close detection sensor (not shown) for detecting the opening / closing of 10 is provided, and the contact angle θ of the front hook 15F with the pin 17 when closing the paper discharge door 10 is smaller than that of the rear hook (not shown). It is set.

Therefore, according to the present embodiment, the front hook 15F is more easily engaged with the pin 17 when closing the paper discharge door 10. Therefore, when the paper discharge door 10 is partially closed, The front side of the discharge door 10 is always closed and the rear side is opened, and the same effect as the second embodiment can be obtained.

Also in this embodiment, as in the second embodiment, when the open / close detection sensor detects that the paper discharge door 10 is at least partially closed, the image forming operation cannot be performed. Can be

In the above first to third embodiments, the discharge door 10 is referred to, but the recording material P as shown in FIG. 4 is used.
Paper discharge door 1 for other doors 50 that have an integrated transport path
Of course, the same configuration as 0 can be used.

[0063]

As is apparent from the above description, according to the first aspect of the present invention, since the reaction force corresponding to the external force acting on the door in the closed state of the door acts on the door from the elastic member, the door is twisted. Deformation can be prevented, and the door can be reliably positioned and fixed with respect to the apparatus main body, and the skew and jam of the recording medium can be prevented.

According to the invention described in claim 2, in the invention described in claim 1, since the handle is provided on the side opposite to the side where the opening / closing detection means is provided with respect to the center line of the door, when the door is closed. The side where the opening / closing detection means is provided is more likely to be twisted than the other side with the handle of the door as a boundary. Therefore, when the door is partially closed, the side with less twist is always closed, and the easily twisted side is opened. In such a case, it is possible to obtain the effect that the user can confirm that the door is completely closed by the detection of the opening / closing detection means installed on the side that is easily twisted.

According to the invention of claim 3, in the invention of claim 1, the hook on the side opposite to the side on which the opening / closing detection means is provided has a smaller contact angle with the hook receiving portion. It is easier for the hook to smoothly engage with the hook receiving portion, and when the door is closed, the side provided with the opening / closing detection means of the door must be opened, which is the same as the invention according to claim 2. The effect is obtained.

According to the invention described in claim 4, in the invention described in claim 2 or 3, the driving force transmitting means to the paper discharge roller and the opening / closing detecting means are provided on the same side with respect to the door center line. When it is possible to confirm that the door is completely closed by the open / close detection means, at the same time, a reliable mechanical operation of the driving force transmission means is ensured, and a stable operation of the discharge roller is ensured. Is obtained.

According to the invention of claim 5, claim 2,
In the invention described in 3 or 4, when the opening / closing detection means detects that the door is at least partially closed, the image forming operation is disabled, and thus the door is fully closed. In addition, it is possible to eliminate the problem that the image forming operation is started without the user's knowledge.

[Brief description of drawings]

FIG. 1 is a perspective view of a sheet discharge unit of an image forming apparatus according to a first exemplary embodiment of the present invention.

FIG. 2 is a perspective view of a sheet discharge unit of the image forming apparatus according to the second exemplary embodiment of the present invention.

FIG. 3 is a side view of a paper discharge door showing a third embodiment of the present invention.

FIG. 4 is a vertical cross-sectional view showing the basic configuration of a conventional color electrophotographic copying machine.

FIG. 5 is a perspective view of an electrophotographic copying machine showing a conventional example of a structure for fixing and fixing a discharge door.

FIG. 6 is a side view showing an engaged state of a hook of a paper discharge door with a pin (hook receiving portion).

[Explanation of symbols]

 1 Photosensitive drum (image carrier) 10 Paper discharge door (door) 15F, 15R Hook 16 Handle 17 Pin (hook receiving part) 25 Elastic member 50 Door 100 Device main body G1, G2 Gear (driving force transmission means) M Paper discharge door Center line (door center line) P Recording material (recording medium) θ Hook contact angle with hook receiving part

Claims (5)

[Claims] 1. An image forming apparatus for transferring a visible image formed on an image carrier according to image information to a recording medium and ejecting the recording medium to the outside of the main body of the apparatus, in which a conveying path of the recording medium is partly provided. A door that can be opened and closed, a pair of hooks that are provided on the left and right of the door, a hook receiving portion that is provided on the apparatus body side, and a counteracting force that acts on the door when the door is closed. An image forming apparatus comprising: an elastic member that generates force. 2. An opening / closing detection means for detecting opening / closing of the door by maintaining the actuator against the elastic force of the door on either one of the left and right sides of the door and opening / closing operation of the door. The image forming apparatus according to claim 1, wherein a handle to be held at some times is provided closer to a side opposite to a side where the opening / closing detection unit is provided with respect to a door center line. 3. A door opening / closing detection means for detecting opening / closing of the door is provided on either the left or right side of the door, and the hook receiving portion of the hook opposite to the side on which the opening / closing detection means is provided. The image forming apparatus according to claim 1, wherein the contact angle of the hook is set smaller than that of the other hook. 4. The door has at least a pair of paper discharge rollers, and the driving force transmission means to the paper discharge rollers and the opening / closing detection means are provided on the same side with respect to the door center line. The image forming apparatus according to claim 2 or 3. 5. The image forming operation is disabled when the opening / closing detecting means detects that the door is in the one-sided open state.
Alternatively, the image forming apparatus according to item 4.